After agents arrest a drug cartel chieftain named Jesus Audel Miramontes-Varela, he becomes one of the bureau's most valuable sources of information, according to confidential interview reports.

WASHINGTON — Police and federal agents pulled the car over in a suburb north of Denver. An FBI agent showed his badge. The driver appeared not startled at all. "My friend," he said, "I have been waiting for you."

And with that, Jesus Audel Miramontes-Varela stepped out of his white 2002 BMW X5 and into the arms of the Federal Bureau of Investigation.

Over the next several days at his ranch in Colorado and an FBI safe house in Albuquerque, the Mexican cartel chieftain — who had reputedly fed one of his victims to lions in Mexico — was transformed into one of the FBI's top informants on the Southwest border.

Around a dining room table in August 2010, an FBI camera whirring above, the 34-year-old Miramontes-Varela confessed his leadershipin the Juarez cartel, according to 75 pages of confidential FBI interview reports obtained by The Times/Tribune Washington Bureau.

He told about marijuana and cocaine routes to California, New York and the Great Lakes. He described the shooting deaths of 30 people at a horse track in Mexico, and a hidden mass grave with 20 bodies, including two U.S. residents.

He told them about his African lions, which he had acquired as circus cubs. The story about feeding one of his enemies to them was false, he claimed, but he said he had seen plenty of "violence and suffering." He told agents he was desperate to trade his knowledge for government protection.He wanted a new life for himself and his wife and three daughters.

A week later Miramontes-Varela pleaded guilty in federal court in New Mexico to a minor felony as an illegal immigrant in possession of a firearm. Then he disappeared, almost certainly into the federal witness protection program.

During the interview sessions, Miramontes-Varela "provided significant information about drug trafficking activity," the documents said, leading to several successful unnamed law enforcement operations in the U.S. and Mexico.

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After Miramontes-Varela was stopped in Brighton, Colo., agents took him back to his ranch. They advised him and his wife, Mari, that he was "the subject of an FBI investigation for his involvement in drug trafficking, firearms trafficking, money laundering and the interstate transportation of stolen property."

In Spanish, they read him his Miranda rights. He called an attorney; they spoke quietly in Spanish. Miramontes-Varela hung up and turned to the agents. "Yes," he said. "He told me to do as much as I can for you."

Miramontes-Varela signed the Miranda waiver and looked up at the agents. He asked, "Where do you want to start?"

First, they said, any guns?

Miramontes-Varela mentioned a black 9-millimeter semiautomatic Glock pistol he said he bought after being shot at in El Paso. The agents asked to see it. "Yes, yes, no problem," he said. He walked to a floor safe in a far corner of the living room, unlocked it and handed the weapon over.

Agents drove the couple to the FBI safe house in Albuquerque. Inside, they pointed to two cameras. One was in the master bedroom, where Miramontes-Varela and his wife would stay. Agents showed that that it was unplugged and that they had covered it with a white plastic bag. "Very nice," Miramontes-Varela said.

Miramontes-Varela talked to them around the dining room table. That is where the other camera was. It stayed on.

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His story poured out. He was born the third of 10 children in Terrero, Mexico, and grew up in Namiquipa, northern Mexico. He married when he was 18, his bride 15. They sneaked though Nogales, Ariz., coming to the U.S., he said, "to make money."

They settled in Denver. Miramontes-Varela installed drywall. But in the late 1990s a brother, Yovany, lost an arm in a tractor mishap, and Miramontes-Varela returned home. He grew apples and traded in cattle.

In early 2002, he said, the Juarez cartel came to Namiquipa. Pedro Sanchez, known as El Tigre, controlled things. He offered Miramontes-Varela a job collecting a monthly $35,000 "tax" from marijuana growers.

Every 15 days, growers carted 20 tons to a local warehouse. It was shipped north through El Paso, the proceeds funneled back to the cartel and the growers.

One day the military arrived and gunfire ensued. "The mayor and town treasurer were killed," Miramontes-Varela said. Later, El Tigre was arrested.

In 2008, Miramontes-Varela said, he fled with his family to El Paso. When he failed to return, the cartel burned his ranch and stole his cattle, all 120 cows. He was done with the violence, he said.

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That part, according to the FBI, was not true. Miramontes-Varela shuffled between ranches in New Mexico and Colorado, they said, often in an armored car with bodyguards, and set up his own drug- and gun-smuggling operation.